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HiRISE and Mars Polar Lander
lyford
post Jun 2 2008, 03:59 PM
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QUOTE (claurel @ Jun 1 2008, 07:29 PM) *
Another backshell rock sculpture from 005536_1030? Or an actual piece of MPL?

Regardless, that is a cool feature smile.gif


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On_2_Vesta
post Sep 11 2009, 05:01 PM
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There is a roughly circular bright object at pixel 36359,42905 of image ESP_013289_1035_RED.jp2. Within this object, on the right side, is a smaller white circle that might be the backshell and which measures 8 or 9 pixels (~ 2-2.25 m) in diameter. It is most brightly lit roughly in its center. Bunched up against this putative backshell, mostly on its left side, would then be the lumpy collapsed parachute. Stretching to the upper right for about 10 meters is a faint stringy-looking feature that would then be the parachute cords laid out and then doubled back. Judging from the HiRise image which includes Phoenix’s parachute cords, so the length here is about right.

This information was presented to the HiRise principal investigator who dismissed it, but he made several errors in his short reply. He apparently looked at the whole object, measured it at 4.5 meters and then stated that nothing on MPL was that large. In fact, the inflated parachute could measure as much as 8.4 meters across, so 4.5 m would seem plausible for a collapsed parachute plus backshell. His second argument was that the candidate was not sufficiently different from the terrain. This is a subjective call, but at the 1:1 scale, or a few steps up or down, there is nothing in the terrain resembling it in the field of view. It does catch the eye. Mine, at least.

Finally, as near as I can make out its lat/lon, it is at 76.55 S, 165.45 E. This is very near the center of the 2 sigma ellipse for the reconstructed trajectory.

I don’t know that it is a part of the MPL hardware, but that after scouring through several HiRise images of the area, this was the only plausible candidate I saw.

P. Fieseler

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vikingmars
post Oct 23 2009, 09:40 AM
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QUOTE (On_2_Vesta @ Sep 11 2009, 07:01 PM) *
I don’t know that it is a part of the MPL hardware, but that after scouring through several HiRise images of the area, this was the only plausible candidate I saw.
P. Fieseler


smile.gif Very interesting and great search.
But looking at it closely, it seems that this "white circle" casts NO shadows, unlike other features nearby (and unlike other backshells saw on MOC images).
Also, the "parachute" is not really different from lighter ground nearby...
Bon courage for your search ! smile.gif
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ElkGroveDan
post Oct 23 2009, 03:13 PM
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QUOTE (vikingmars @ Oct 23 2009, 02:40 AM) *
But looking at it closely, it seems that this "white circle" casts NO shadows, unlike other features nearby


Of course if you dropped something from 100 meters it would tend to acquire a flattened shape and therefore cast no shadows smile.gif

I will say that this is the most interesting of any of the candidate objects I've seen. My sense is that it's too big?


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On_2_Vesta
post Oct 23 2009, 10:26 PM
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Thanks for taking the time to respond. It is admittedly an ambiguous object, but I wonder if people are seeing the shapes the way that I am. I will attempt to repost the image with a cartoon of what I see (or imagine that I see). The details, especially the parachute cords, are clearer in the viewer than these posted jpegs.

A parachute flat on the ground would not cast a shadow. An intact back-shell should, however. Perhaps the soil there is soft or mobile.


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nprev
post Oct 23 2009, 11:01 PM
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Vesta, I think your "parachute cords" are actually a small bluff, and are the lower right edge of a small hill on which your interestingly VERY round small thing on top of a bigger round thing lies.

Definitely worth another look, preferably with a different illumination angle.


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vikingmars
post Oct 25 2009, 08:15 PM
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QUOTE (ElkGroveDan @ Oct 23 2009, 05:13 PM) *
Of course if you dropped something from 100 meters it would tend to acquire a flattened shape and therefore cast no shadows smile.gif


Not crushed as flat as this, being slowed down at least a little by a parachute. All other backshells came down fairly intact as seen on images taken for other missions by MRO (Viking, Pathfinder, MER) and the lander themselves (MER) ( cool.gif
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Greg Hullender
post Oct 25 2009, 11:53 PM
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ElkGroveDan
post Oct 26 2009, 12:03 AM
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QUOTE (vikingmars @ Oct 25 2009, 01:15 PM) *
Not crushed as flat as this, being slowed down at least a little by a parachute.

I was sort of joking, imagining a coyote-roadrunner cartoon. But the present theory is that the descent thrusters cut off when the landing legs deployed around 100 feet prior to touchdown, so the parachute was long gone. One could imagine however a soft soil where the craft did a combination of collapsing and embedding such that you have a debris pile that casts little or no shadow.


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nprev
post Oct 26 2009, 12:39 AM
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A thought just occurred to me: If the thrusters did cut off prematurely as in one of the leading theories, would MPL still have been aerodynamically stable during the fall?

I don't know if the atmosphere would have had any significant effect during that short distance (even if it was windy), nor do I know where the vehicle's center of gravity was located. Did MPL have static stability, or were the thrusters totally necessary to keep it normal to Mars' gravity at this stage of the descent?

This could definitely have some bearing on how the wreckage might appear from MRO.


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Geert
post Oct 26 2009, 01:10 AM
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QUOTE (nprev @ Oct 26 2009, 08:39 AM) *
This could definitely have some bearing on how the wreckage might appear from MRO.


I think a lot will also depend on how Phoenix looks to MRO after the ice has disappeared. The wreckage of MPL has been embedded in ice at least once before most of the available images were made, so how much effect does this have on for instance the parachute, will this still be visible after one winter or will it be completely covered by dust and dirt?

The terrain at the MPL site is just terrible, you can easily hide hundreds of landers over there. Quite apart from that, there is so much uncertainty about the final fate that we can't be sure what we are searching for, if the engines indeed did cut off 100 feet of so above the ground then I would guess we will be looking at a mostly intact craft, more or less similar to Phoenix, but if it failed very early in the EDL then you might never recognize it. One point is, if it failed very late, why didn't we ever hear anything from the two penetrator-probes which were released very early?
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ElkGroveDan
post Oct 26 2009, 03:07 AM
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QUOTE (Geert @ Oct 25 2009, 06:10 PM) *
but if it failed very early in the EDL then you might never recognize it. One point is, if it failed very late, why didn't we ever hear anything from the two penetrator-probes which were released very early?


From what I heard those probes were so badly designed and not tested to the standards we might expect, that had MPL succeeded we probably never would have heard from them anyway. But I'm just reporting anecdotal recollections. I'll have to look up the specifics.


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djellison
post Oct 26 2009, 08:11 AM
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The most likely failure as the investigation concluded, would be an early shut down of thrusters. This means, on the surface, there should be a heatshield, like Phoenix, a Backshell and Parachute, like Phoenix, and a crashed lander.

I'm still looking at the PHX landing sites HiRISE images of the new season, trying to find the landing site - and can't.
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imipak
post Oct 26 2009, 08:07 PM
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Whilst casually poking around to see if I could turn up a copy of that report, I came across this story reporting Michael Malin "possibly" identifying the MPL wreckage. Has this site been reimaged by HiRISE? I haven't found subsequent news on this site, probably my google-fu is weak...


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Phil Stooke
post Oct 26 2009, 08:12 PM
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Yes it has been seen by HiRISE, but even before that it was re-imaged by MGS. Malin withdrew his interpretation of that feature, and now we don't know where it is. The HiRISE image is on here somewhere if you look back.

Phil


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